Temporary protective film for semiconductor device manufacturing and method for manufacturing semiconductor devices

Abstract

A temporary protective film for manufacturing a semiconductor device comprises: a support film; and an adhesive layer disposed on the support film, the adhesive layer containing: a polymer, wherein the monomer units include alkyl methacrylate, methacryloylmorpholine and a monomer having a crosslinking group; and a crosslinking agent capable of crosslinking with the crosslinking group, wherein the content of methacryloylmorpholine is 7% by mass or more based on the total amount of monomer units in the polymer.

Description

Technical Field

[0001] The present disclosure relates to a temporary protective film for semiconductor device manufacturing and a method for manufacturing the semiconductor device. Prior Art

[0002] Semiconductor packages sometimes use a structure in which a sealing layer is formed only on the semiconductor element side of a lead frame, leaving the backside of the lead frame exposed. During the manufacture of semiconductor packages with this structure, there is a risk that the sealing material may be wrapped around the backside of the lead frame when the sealing layer is formed. To prevent this, a method is known in which a temporary protective film is applied to the backside of the lead frame (Patent Document 1). After the sealing layer is formed, the temporary protective film is peeled off the lead frame.

[0003] [Patent Document 1] International Publication No. 2001 / 035460

[0004] It is desirable for a temporary protective film to have excellent adhesion to an adherend such as a lead frame at room temperature (e.g., 25°C), while also ensuring that no adhesive components remain on the adherend when the temporary protective film is peeled off. However, achieving this balance is not always easy. Summary of the Invention

[0005] Therefore, an object of one aspect of the present invention is to provide a temporary protective film that has excellent adhesion at room temperature and can prevent residue from remaining on an adherend during peeling.

[0006] The present inventors conducted research on using a polymer containing, as monomer units, an alkyl (meth)acrylate, (meth)acryloylmorpholine, and a monomer having a crosslinking group in the adhesive layer of a temporary protective film. The results revealed that when the (meth)acryloylmorpholine content is at least a specific amount, both excellent adhesion at room temperature and reduced residue on the adherend can be achieved.

[0007] The present invention includes the following aspects. [1] A temporary protective film for semiconductor device manufacturing, comprising: a supporting film; and an adhesive layer provided on the supporting film, the adhesive layer comprising: a polymer comprising, as monomer units, an alkyl (meth)acrylate, (meth)acryloyl morpholine, and a monomer having a crosslinking group; and a crosslinking agent capable of crosslinking with the crosslinking group, wherein the content of (meth)acryloyl morpholine is 7% by mass or more based on the total amount of monomer units in the polymer. [2] The temporary protective film as described in [1], wherein the crosslinking group is an acidic group and the crosslinking agent has an epoxy group. [3] The temporary protective film as described in [2], wherein the crosslinking agent further has an amino group. [4] The temporary protective film according to any one of [1] to [3], wherein the crosslinking agent has a group represented by the following formula (1). [Chemistry 1] [5] A method for manufacturing a semiconductor device, which comprises, in sequence: a step of attaching a temporary protective film to one side of a substrate; a step of mounting a semiconductor element on the surface of the substrate opposite to the temporary protective film; a step of sealing the semiconductor element; and a step of peeling the temporary protective film from the substrate, wherein the temporary protective film comprises: a supporting film; and an adhesive layer provided on the supporting film, the adhesive layer comprising: a polymer, comprising as monomer units a monomer having (meth)acrylate, (meth)acryloylmorpholine and a crosslinking group; and a crosslinking agent capable of crosslinking with the crosslinking group, wherein the content of (meth)acryloylmorpholine is 7% by mass or more based on the total amount of monomer units in the aforementioned polymer. [6] The manufacturing method as described in [5], wherein the crosslinking group is an acidic group and the crosslinking agent has an epoxy group. [7] The manufacturing method as described in [6], wherein the cross-linking agent further has an amino group. [8] The production method as described in any one of [5] to [7], wherein the crosslinking agent has a group represented by the following formula (1). [Chemistry 2] [Effects of the Invention]

[0008] According to one aspect of the present invention, a temporary protective film can be provided which has excellent adhesion at room temperature and can prevent residue from remaining on an adherend during peeling. Simple diagram description

[0009] FIG1 is a cross-sectional view showing one embodiment of a temporary protective film. FIG2 is a cross-sectional view illustrating one embodiment of a method for manufacturing a semiconductor device. FIG3 is a cross-sectional view illustrating one embodiment of a method for manufacturing a semiconductor device. FIG4 is a cross-sectional view showing one embodiment of a semiconductor device. FIG5 is a perspective view showing an embodiment of a reel body. Implementation Method

[0010] The following describes an embodiment of the present invention. FIG1 is a cross-sectional view of a temporary protective film according to one embodiment. As shown in FIG1 , a temporary protective film 10 according to one embodiment comprises a support film 1 and an adhesive layer 2 provided on the support film 1. The temporary protective film 10 can be used as a temporary protective film for semiconductor device manufacturing. The temporary protective film 10 is attached to the back side of the lead frame (the side opposite to the side on which the semiconductor element is mounted) during the sealing molding step of forming a sealing layer for sealing a semiconductor element mounted on a die pad of a lead frame, and can be used as a temporary protective film for semiconductor sealing molding to temporarily protect the lead frame during the sealing molding.

[0011] The support film 1 can be, for example, at least one polymer film selected from the group consisting of polyimide, polyamide, polyamide-imide, polysulfone, polyethersulfone, polyphenylene sulfide, polyetherketone, polyarylate, polyetheretherketone, and polyethylene naphthalate. A polyimide film is preferred. The polyimide can be an aromatic polyimide. The support film 1 can be a copper, aluminum, stainless steel, or nickel film. When the support film 1 is a polymer film, its surface can be treated by chemical treatments such as alkali treatment and silane coupling agent treatment, physical treatments such as sand pad treatment, plasma treatment, and corona treatment.

[0012] The thickness of the support film 1 can be, for example, 5 μm or greater, but can also be 100 μm or less, or 50 μm or less. The ratio T 2 / T 1 of the thickness T 2 of the adhesive layer 2 to the thickness T 1 of the support film 1 can be 0.1 or greater, but can also be 0.5 or less, 0.3 or less, or 0.2 or less.

[0013] The adhesive layer 2 contains a polymer (hereinafter also referred to as "acrylic polymer") containing, as monomer units, alkyl (meth)acrylate, (meth)acryloylmorpholine, and a monomer having a crosslinking group (hereinafter also referred to as "crosslinking monomer").

[0014] The alkyl group (excluding the (meth)acryloyl group) in the alkyl (meth)acrylate may be linear or branched. The number of carbon atoms in the alkyl group may be 2 or more, 3 or more, 30 or less, 20 or less, 10 or less, 7 or less, 5 or less, or 4 or less, or 2 or 4.

[0015] Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, and decyl (meth)acrylate.

[0016] In addition to a crosslinking group, the crosslinking monomer also has a polymerizable group capable of copolymerizing with the (meth)acrylate and (meth)acryloylmorpholine. The polymerizable group may be, for example, an ethylenically unsaturated group. The crosslinking group may be, for example, an acidic group. Examples of the acidic group include a carboxyl group or a sulfonyl group, with a carboxyl group being preferred.

[0017] Examples of the crosslinking monomer having a carboxyl group include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, monohydroxyethyl phthalate acrylate, and 2-acryloyloxyethyl succinate.

[0018] Acrylic polymers may further contain monomers other than alkyl (meth)acrylates, (meth)acryloylmorpholine, and crosslinking monomers as monomer units. Examples of these monomers include monomers having polymerizable groups (e.g., ethylenically unsaturated groups) and hydroxyl groups. Examples of these monomers include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate; and hydroxyalkyl (meth)acrylate cycloalkanes such as (4-hydroxymethylcyclohexyl) (meth)acrylate.

[0019] The (meth)acryloylmorpholine content in the acrylic polymer is 7% by mass or greater, based on the total amount of monomer units in the acrylic polymer. This provides a temporary protective film that exhibits excellent adhesion at room temperature and minimizes residue on the adherend during peeling. The (meth)acryloylmorpholine content, based on the total amount of monomer units in the acrylic polymer, can be 7.5% by mass or greater, 8% by mass or greater, 8.5% by mass or greater, or 9.0% by mass or greater, and is preferably 20% by mass or less, 18% by mass or less, 17% by mass or less, 16.5% by mass or less, or 16% by mass or less.

[0020] The content of the alkyl (meth)acrylate, based on the total amount of monomer units in the acrylic polymer, may be 70% by mass or more, 75% by mass or more, or 80% by mass or less, or 92% by mass or less, 90% by mass or less, or 88% by mass or less.

[0021] The content of the crosslinking monomer may be 1% by mass or more, 2% by mass or more, or 3% by mass or less, or 10% by mass or less, 6% by mass or less, or 4% by mass or less, based on the total amount of monomer units in the acrylic polymer.

[0022] Based on the total amount of monomer units in the acrylic polymer, the content of other monomers may be 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or less, or 5% by mass or less, 4% by mass or less, or 3% by mass or less.

[0023] The mass ratio of the (meth)acryloylmorpholine content to the (meth)acryloylmorpholine content to the alkyl (meth)acrylate content ((meth)acryloylmorpholine / alkyl (meth)acrylate) may be 0.08 / 1 or more, 0.09 / 1 or more, or 0.1 / 1 or less, or 0.3 / 1 or less, 0.25 / 1 or less, 0.23 / 1 or less, 0.21 / 1 or less, or 0.2 / 1 or less.

[0024] The acid value of the acrylic polymer can be 10 mgKOH / g or greater, or 20 mgKOH / g or greater, or 40 mgKOH / g or less, or 30 mgKOH / g or less. The hydroxyl value of the acrylic polymer can be 1 mgKOH / g or greater, or 2 mgKOH / g or greater, or 10 mgKOH / g or less, or 5 mgKOH / g or less. The acid value and hydroxyl value of the acrylic polymer are measured according to the method described in JIS K0070.

[0025] The content of the acrylic polymer based on the total amount of the adhesive layer 2 may be 80% by mass or more, 85% by mass or more, or 90% by mass or less, or 99.5% by mass or less.

[0026] The adhesive layer 2 further contains a crosslinking agent. The crosslinking agent is capable of crosslinking with the crosslinkable groups in the acrylic polymer. Known crosslinking agents can be used as such. When the crosslinkable groups in the acrylic polymer are acidic groups, the crosslinking agent preferably contains an epoxy group. The number of epoxy groups in the crosslinking agent may be 2 or more, 3 or more, 4 or less, or even 4.

[0027] In one embodiment, the crosslinking agent may have an amine group in addition to an epoxy group. The amine group may be an amine group in which the hydrogen atom in the -NH2 group is replaced (a substituted amine group), or a tertiary amine group. This crosslinking agent may have a group represented by the following formula (1). [Chemistry 3] The number of the groups represented by the above formula (1) in the cross-linking agent may be 1 or 2.

[0028] The cross-linking agent may be a cross-linking agent represented by the following formula (2). [Chemistry 4] In the formula, X represents a divalent hydrocarbon group.

[0029] The divalent hydrocarbon group represented by X may be a divalent hydrocarbon group having a ring. The ring may be an aliphatic ring or an aromatic ring. The number of carbon atoms constituting the ring may be 5 or more, 8 or less, or 6. The number of rings in the divalent hydrocarbon group may be 1 or more, 3 or less, or 1 or 2. When the divalent hydrocarbon group contains multiple rings, the multiple rings may be bonded to each other or to an alkylene group having 1 to 3 carbon atoms.

[0030] The divalent hydrocarbon group represented by X preferably has a cycloalkylene group. The cycloalkylene group may have 5 or more carbon atoms, or 8 or less carbon atoms. The cycloalkylene group is preferably a cyclohexylene group.

[0031] In one embodiment, the crosslinking agent may be a crosslinking agent having an ether group in addition to an epoxy group (without an amino group). Such a crosslinking agent may have a group represented by the following formula (3). [Chemistry 5] The number of groups represented by the above formula (3) in the cross-linking agent may be 2 or more, 3 or more, 4 or less, or 2 or 4.

[0032] The cross-linking agent may be a cross-linking agent represented by the following formula (4). [Chemistry 6] In the formula, m represents an integer of 2 or greater, n represents an integer of 0 or greater, and A represents a residue obtained by removing a hydroxyl group from an (m+n)-valent polyol.

[0033] m may be an integer greater than or equal to 3, or an integer less than or equal to 4, or 2 or 4. n may be an integer greater than or equal to 1, or an integer less than or equal to 2, or 0 or 2. m+n may be an integer greater than or equal to 2, or an integer less than or equal to 6.

[0034] The polyol in A can be an aliphatic polyol or a polyol having an ether group. The aliphatic polyol can have 2 or more, 3 or more, or 4 or more carbon atoms, or 10 or less, 9 or less, or 8 or less. The polyol having an ether group can be a polyalkylene glycol such as polyethylene glycol.

[0035] The crosslinking agent preferably has the epoxy group and the amine group mentioned above. In this case, it is possible to suppress the deterioration of the appearance of the adherend after the temporary protective film is peeled off from the adherend (for example, the formation of an unwanted pattern on the adherend).

[0036] The content of the crosslinking agent can be 0.5% by mass or more, 15% by mass or less, or 10% by mass or less, based on the total amount of the adhesive layer 2. From the perspective of suppressing deterioration of the appearance of the adherend after the temporary protective film is peeled off from the adherend, 1% by mass or more, 2% by mass or more, or 2.5% by mass or more is preferred.

[0037] The content of the crosslinking agent relative to 100 parts by mass of the acrylic polymer may be 0.5 parts by mass or more, 15 parts by mass or less, or 10 parts by mass or less. From the perspective of suppressing deterioration in the appearance of the adherend after the temporary protective film is peeled off from the adherend, the content is preferably 1 part by mass or more, 2 parts by mass or more, or 3 parts by mass or more.

[0038] The adhesive layer 2 may further contain other components in addition to the acrylic polymer and the crosslinking agent. Examples of other components include polymers other than the acrylic polymer and coupling agents.

[0039] The thickness of the adhesive layer 2 can be greater than 1 μm, greater than 2 μm, greater than 3 μm, greater than 4 μm or greater than 5 μm, or less than 20 μm, less than 18 μm, less than 16 μm, less than 14 μm, less than 12 μm or less than 10 μm.

[0040] In another embodiment, the temporary protective film may further include a cover film disposed on the surface of the adhesive layer opposite the support film. That is, the temporary protective film may include a support film, an adhesive layer, and a cover film in this order. The cover film may be a polyethylene terephthalate film. The thickness of the cover film may be greater than 10 μm or less than 100 μm.

[0041] In another embodiment, the temporary protective film may further include a non-adhesive layer disposed on the side of the support film opposite the adhesive layer. The non-adhesive layer may be a resin layer that exhibits substantially no adhesion to the adherend at temperatures between 0°C and 270°C. The non-adhesive layer may comprise a thermoplastic resin, a thermosetting resin (cured product), or a combination thereof. The non-adhesive layer may further contain fillers (e.g., ceramic powder, glass powder, silver powder, copper powder, resin particles, rubber particles), coupling agents, etc. The thickness of the non-adhesive layer may be greater than 1 μm or less than 10 μm.

[0042] The temporary protective film can be produced, for example, by a method including the steps of forming an adhesive layer by coating a varnish containing an acrylic polymer and a crosslinking agent on a support film and removing the solvent from the coating film.

[0043] Next, a method for manufacturing a semiconductor device using the aforementioned temporary protective film will be described. One embodiment of the semiconductor device manufacturing method sequentially comprises: step S1, attaching a temporary protective film to one side of a substrate; step S2, mounting a semiconductor element on the surface of the substrate opposite the temporary protective film; step S3, sealing the semiconductor element; and step S4, peeling the temporary protective film from the substrate. The following, as an example, describes a method for manufacturing a semiconductor device (semiconductor device package) using a lead frame as the substrate.

[0044] FIG2 is a cross-sectional view illustrating one embodiment of a semiconductor device manufacturing method (step S1). In step S1, as shown in FIG2, a temporary protective film 10 is attached to one surface, or the back surface, of a lead frame 11 having a die pad 11a and inner leads 11b. Temporary protective film 10 is attached so that the adhesive layer of temporary protective film 10 contacts lead frame 11.

[0045] The lead frame 11 can be formed of, for example, an iron alloy such as 42 alloy, copper, or a copper alloy. The lead frame 11 can include a molded body formed of copper or a copper alloy and a coating layer of palladium, gold, silver, or the like covering the surface thereof.

[0046] The temporary protective film 10 has excellent adhesion at room temperature (e.g., 25°C) and can therefore be attached to the lead frame 11 at room temperature. The temporary protective film 10 can be attached to the lead frame 11 while being heated and pressurized. In this case, the heating temperature can be 150°C or higher, or 400°C or lower. The pressure can be 0.5 MPa or higher, or 30 MPa or lower. The heating and pressurizing time can be 1 second or higher, or 60 seconds or lower.

[0047] Figure 3 is a cross-sectional view illustrating one embodiment of a semiconductor device manufacturing method (steps S2 and S3). In step S2, as shown in Figure 3, a semiconductor element 14 is mounted on the surface of die pad 11a opposite to temporary protective film 10. Semiconductor element 14 is bonded to die pad 11a via an adhesive (e.g., silver paste). After bonding semiconductor element 14 to die pad 11a, reflow connection (CuClip connection, etc.) can be performed at a maximum temperature of 250-440°C or 250-400°C for 1-30 minutes.

[0048] Next, the semiconductor element 14 is connected to the inner lead 11b using the wire 12. The wire 12 can be, for example, a gold wire, a copper wire, or a palladium-plated copper wire. The wire 12 can be bonded to the semiconductor element 14 and the inner lead 11b using ultrasonic and pressing pressure while being heated at 200-350°C.

[0049] Next, in step S3, as shown in FIG3, a sealing layer 13 is formed to seal the semiconductor element 14 and the wire 12. Thus, a temporarily protected sealing molded body 20 having the lead frame 11, the semiconductor element 14 and the sealing layer 13 is obtained.

[0050] The sealing layer 13 is formed by seal molding using a sealing material. Through seal molding, a sealed molded body 20 is obtained, which includes the sealing layer 13 that collectively seals the plurality of semiconductor elements 14. A temporary protective film 10 is provided between seal moldings to prevent the sealing material from being drawn onto the back surface of the lead frame 11.

[0051] The temperature during the formation of the sealing layer 13 (temperature of the sealing material) can be 140-200°C or 160-180°C. The pressure during the formation of the sealing layer can be 6-15 MPa or 7-10 MPa. The sealing molding time can be 1-5 minutes or 2-3 minutes.

[0052] The sealing material may include, for example, epoxy resins such as cresol novolac epoxy resin, phenol novolac epoxy resin, biphenyl diepoxy resin, and naphthol novolac epoxy resin, etc. The sealing material may also include fillers, flame retardants such as bromine compounds, wax components, and the like.

[0053] After the sealing layer 13 is formed (seal molding), the temporary protective film 10 is peeled off from the lead frame 11 and the sealing layer 13 of the obtained seal molding 20. When the sealing layer 13 is cured, the temporary protective film 10 can be peeled off at any time before or after the sealing layer 13 is cured.

[0054] The temperature for peeling the temporary protective film 10 is not particularly limited, but can be room temperature (e.g., 5-35°C). This temperature can be above the glass transition temperature of the adhesive layer. In this case, the temporary protective film 10 exhibits improved peelability from the lead frame 11 and the sealing material. If the Tg of the acrylic polymer in the adhesive layer is, for example, below 5°C or below 0°C, the Tg of the adhesive layer is equal to or lower than room temperature, making it easier to achieve good peelability at room temperature.

[0055] When the lead frame 11 includes a plurality of patterns of die pads 11a and inner leads 11b, the molded sealant 20 can be divided as needed to obtain a plurality of semiconductor devices (semiconductor packages) 100 shown in FIG. 4 , each having a single semiconductor element. Specifically, when the lead frame 11 includes a plurality of die pads 11a and a semiconductor element 14 is mounted on each of the plurality of die pads 11a, the manufacturing method of one embodiment can further include the step of peeling the temporary protective film 10 from the molded sealant 20 and then dividing the molded sealant 20 to obtain semiconductor devices (semiconductor packages) 100 having a single die pad 11a and a semiconductor element 14.

[0056] The temporary protective film is in a long strip and can also be used in a roll-like state wound around a core. In this case, the temporary protective film is applied to the adherend while being unwound from the roll.

[0057] Figure 5 is a perspective view of one embodiment of a reel. As shown in Figure 5, the reel 30 in one embodiment comprises a core 31, a temporary protective film 10 wound around the core 31, and side panels 32. The width (length perpendicular to the winding direction) of the core 31 and the temporary protective film 10 can be 1 mm or greater, 5 mm or greater, or 10 mm or less, or 1000 mm or less, 800 mm or less, or 500 mm or less. In another embodiment, the reel may not have side panels. [Example]

[0058] Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to the Examples.

[0059] (Example 1) An acrylic polymer A-1 containing 80% by mass of butyl acrylate (BA), 16% by mass of acryloyl morpholine (ACMO), 3% by mass of acrylic acid, and 1% by mass of other monomers (monomers having hydroxyl groups) as monomer units was prepared. 100 parts by mass of the acrylic polymer A-1 and the following formula (B-1): [Chemistry 7] 10 parts by mass of the crosslinking agent B-1 were dissolved in cyclohexanone to obtain a varnish for forming an adhesive layer.

[0060] A polyimide film (25 μm thick, manufactured by DU PONT-TORAY CO., LTD., product name: Kapton 100EN) was prepared as a support film. The obtained varnish was applied to one side of the support film. The coating on the support film was dried by heating at 90°C for 1.5 minutes and then at 260°C for 1.5 minutes, forming a 5 μm thick adhesive layer. This produced a temporary protective film.

[0061] (Example 2) A temporary protective film was obtained in the same manner as in Example 1, except that acrylic polymer A-2 was used instead of acrylic polymer A-1, in which the BA content and the ACMO content in the monomer composition of acrylic polymer A-1 were changed to 86.5% by mass and 9.5% by mass.

[0062] (Comparative Example 1) A temporary protective film was obtained in the same manner as in Example 1, except that acrylic polymer A-3 was used instead of acrylic polymer A-1, in which the BA content and the ACMO content in the monomer composition of acrylic polymer A-1 were changed to 90.5% by mass and 5.5% by mass, respectively.

[0063] (Example 3) In addition to using the following formula (B-2): [Chemistry 8] A temporary protective film was obtained in the same manner as in Example 1 except that the crosslinking agent B-2 was used instead of the crosslinking agent B-1.

[0064] (Example 4) In addition to using the following formula (B-3): [Chemistry 9] A temporary protective film was obtained in the same manner as in Example 1 except that the crosslinking agent B-3 was used instead of the crosslinking agent B-1.

[0065] (Examples 5 to 8) A temporary protective film was obtained in the same manner as in Example 1 except that the mixing ratio (parts by mass) of the acrylic polymer A-1 and the crosslinking agent B-1 was changed as shown in Table 1.

[0066] (Example 9) A temporary protective film was obtained in the same manner as in Example 1 except that the thickness of the adhesive layer was changed to 10 μm.

[0067] (Evaluation of Adhesion) (1) After application at room temperature EFTEC64TCu sheets (Cu-Fe-P alloy, manufactured by Shinko Electric Industries Co., Ltd.) and CDA194 palladium-plated sheets (PPF, manufactured by Shinko Electric Industries Co., Ltd.) were prepared as adherends. Temporary protective films, cut into 10 mm x 50 mm dimensions, were applied to each of these adherends using a hand roller at 25°C and a load of 20 N, with the adhesive layer in contact with the adherend. Each adherend was then obtained using a force gauge at 25°C and a speed of 50 mm / min, along a 90-degree angle relative to the main surface of the lead frame. The maximum load (N / m) per 10 mm width of the adhesive layer was measured as the adhesive strength (90-degree peel strength) after room temperature adhesion. The results are shown in Table 1.

[0068] (2) Adhesion after heat treatment Each attached body obtained in the same manner as in (1) above was subjected to a heat treatment in an oven under an air atmosphere at 180°C for 60 minutes and then at 200°C for 60 minutes. The temporary protective film was then peeled off at a speed of 50 mm / min using a dynamometer at 25°C in a direction 90 degrees relative to the main surface of the lead frame. The maximum load (N / m) per 10 mm width of the adhesive layer was measured as the adhesive strength after the heat treatment (90-degree peel strength). The results are shown in Table 1.

[0069] (3) Evaluation of residues Each temporary protective film was attached to a CDA194 palladium-plated Cu plate (lead frame, manufactured by Shinko Electric Industries Co., Ltd.) at 25°C and a load of 20N, with the adhesive layer in contact with the lead frame. The resulting bonded body was heated in an oven under air atmosphere, changing the conditions from 180°C for 60 minutes to 200°C for 60 minutes. The surface of the lead frame opposite the temporary protective film was plasma treated under argon atmosphere (flow rate: 20 sccm) at 150 W for 15 seconds.

[0070] Using a molding machine (manufactured by APIC Yamada Corporation), a sealing layer was formed on the surface of the lead frame opposite the temporary protective film using a sealing material (product name: GE-300, manufactured by Showa Denko Materials Co., Ltd.). Sealing conditions were set at 175°C, 6.8 MPa, and 2 minutes. Each temporary protective film was then peeled off at a speed of 50 mm / min at 25°C in a direction 180° relative to the lead frame surface. The state of the adhesive layer remaining on the sealing layer after peeling off the temporary protective film was examined. The ratio of the area occupied by the adhesive layer residue to the surface area of ​​the sealing layer was calculated. The peelability after sealing molding was evaluated based on the ratio of the area occupied by the adhesive layer residue according to the following five criteria. The results are shown in Table 1. 5:60~100% 4: 40% or more and less than 60% 3: 20% or more and less than 40% 2: 10% or more and less than 20% 1: 0% or more and less than 10%

[0071] (4) Evaluation of appearance After each temporary protective film was removed in step (3), the sealant layer was checked for the presence of a portion with a different hue. The appearance after seal molding was evaluated based on the presence or absence of the portion with a different hue according to the following criteria. The results are shown in Table 1. A: There is no part with different hues (almost uniformly black (the color of the sealant)) B: There is a part with a different hue (a white linear area on a black surface)

[0072] [Table 1] Example 1 Example 2 Comparative Example 1 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Mixing ratio (parts by mass) Acrylic polymers A-1 100 - - 100 100 100 100 100 100 100 A-2 - 100 - - - - - - - - A-3 - - 100 - - - - - - - crosslinking agent B-1 10 10 10 - - 7 5 3 0.71 10 B-2 - - - 10 - - - - - - B-3 - - - - 10 - - - - - Thickness of adhesive layer (μm) 5 5 5 5 5 5 5 5 5 10 evaluate result Adhesion after attaching at room temperature (N / m) Cu twenty one twenty two 10 29 44 20 20 35 60 36 PPF 28 25 16 40 53 26 28 26 75 42 Adhesion after heat treatment (N / m) Cu 44 48 30 38 70 45 50 50 90 98 PPF 63 74 41 35 78 50 53 60 93 85 residue 1 1 3 1 1 1 1 1 1 1 Appearance A A A B B A A A B A

[0073] 1: Support membrane 2: Adhesion layer 10: Temporary protective film 11:Lead frame 11a: Wafer pad 11b: Inner lead 12: Wire 13: Sealing layer 14: Semiconductor components 20: Sealing molding 100:Semiconductor device

Claims

1. A temporary protective film for manufacturing a semiconductor device, comprising: a support film; and an adhesive layer disposed on the support film, the adhesive layer comprising: a polymer, wherein the monomer units include alkyl (meth)acrylate having 4 or fewer carbon atoms, (meth)acrylomorpholine, and a monomer having a crosslinking group; and a crosslinking agent capable of crosslinking with the aforementioned crosslinking group, wherein, based on the total amount of monomer units in the polymer, the content of the alkyl (meth)acrylate having 4 or fewer carbon atoms is 70% by mass or more, and the content of the (meth)acrylomorpholine is 7% by mass or more, based on the total amount of monomer units in the polymer.

2. The temporary protective film as claimed in claim 1, wherein the aforementioned crosslinking group is an acidic group and the aforementioned crosslinking agent has an epoxy group.

3. The temporary protective film as claimed in claim 2, wherein the aforementioned crosslinking agent further has an amine group.

4. A temporary protective film as described in any one of claims 1 to 3, wherein the aforementioned crosslinking agent has a base represented by the following formula (1), [Chemical 1].

5. A method for manufacturing a semiconductor device, comprising, in sequence: a step of attaching a temporary protective film to one side of a substrate; a step of mounting a semiconductor element on a surface of the substrate opposite to the temporary protective film; a step of sealing the semiconductor element; and a step of peeling the temporary protective film off the substrate, wherein the temporary protective film comprises: a support film; and an adhesive layer disposed on the support film, wherein the adhesive layer comprises: a polymer, wherein the monomer units include alkyl (meth)acrylate having 4 or fewer carbon atoms, (meth)acrylomorpholine, and a monomer having a crosslinking group; and a crosslinking agent capable of crosslinking with the crosslinking group, wherein, based on the total amount of monomer units in the polymer, the content of the alkyl (meth)acrylate having 4 or fewer carbon atoms is 70% by mass or more, and the content of (meth)acrylomorpholine is 7% by mass or more, based on the total amount of monomer units in the polymer.

6. The manufacturing method as described in claim 5, wherein the aforementioned crosslinking group is an acidic group and the aforementioned crosslinking agent has an epoxy group.

7. The manufacturing method as described in claim 6, wherein the aforementioned crosslinking agent further contains an amine group.

8. The manufacturing method as described in any one of claims 5 to 7, wherein the aforementioned crosslinking agent has a base represented by the following formula (1), [Chemical 2].

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